This disclosure relates to apparatus in the form of a kit of medical instruments used for surgically implanting an electric neurostimulation lead in the human sacrum.
The medical device industry produces a wide variety of electronic and mechanical devices for treating patient medical conditions. Depending upon the medical condition, medical devices can be surgically implanted or connected externally to a patient receiving treatment. Clinicians use medical devices alone or in combination with drug therapies and surgery to treat patient medical conditions. For some medical conditions, medical devices provide the best, and sometimes the only, therapy to restore an individual to a more healthful condition and a fuller life. Conditions that medical devices can effectively treat include pelvic floor disorders.
Pelvic floor disorders adversely affect the health and quality of life of millions of people. Pelvic floor disorders include urinary control disorders such as urge incontinency, urge frequency, voiding efficiency, fecal control disorders, sexual dysfunction, and pelvic pain. Individuals with urinary control disorders often face debilitating challenges in their everyday lives. These individuals can be preoccupied with trips to the bathroom, fears of embarrassment, and sleepless nights. Some suffers become so anxious that they become isolated and depressed. Pelvic floor disorders can be treated with a variety of therapeutic options such as behavior modification including biofeedback, pharmacological treatment, mechanical intervention such as self-catheterization, physical appliances such as diapers, and surgical intervention. Surgical treatments are the most invasive and are often considered after other therapies have proven ineffective.
One surgical technique to treat urinary control disorders is the implantable InterStim® therapy, available from Medtronic, Inc., which applies mild electrical stimulation to the sacral nerves in the lower region of the spine to influence behavior of structures such as the bladder, sphincter and pelvic floor muscles. Generally, implantation of InterStim therapy involves surgically implanting a stimulation lead near the sacral nerves. The stimulation lead is a very small, insulated electrical conductor with electrical stimulation contacts on the distal end placed near the sacral nerves and an electrical connector on the opposite proximal end of the lead. The lead electrical connector is typically connected to a small extension, and the extension is connected to a small neurostimulator that operates similar to a cardiac pacemaker by delivering occasional small electrical pulses that sometimes create a tingling sensation felt by the patient. The stimulation lead, lead extension, and neurostimulator are all implanted in the patient in a manner that is typically not perceptible by others. InterStim therapy can improve the condition of a pelvic floor disorder patient and allow the patient to lead a full life. Also, InterStim therapy is nondestructive and reversible.
Previous surgical methods and apparatus used to implant a neurostimulation lead in a patient's sacrum to treat pelvic floor disorders have been invasive by requiring a large sacral incision in a procedure known as dissection. FIG. 1a (prior art) shows a sacral dissection. Dissection involves making a midline incision over the sacrum from a little below S4 up to S1 that in an adult ranges from about 7.62 cm (3.0 inches) to 12.7 cm (5.0 inches). After the incision is made, the fascia lateral to the midline is cleaned off and divided in the direction of the incision approximately one finger width lateral to the midline. Next, the paraspinal muscle fibers are split and sharply retracted. Once the muscle fibers are retracted, the sacral foramen is exposed while preserving the periosteum. Next, the desired foramen is located by observing anatomical landmarks and palpating for a marble-board-like depression in the posterior sacral surface. FIG. 1b (prior art) shows a foramen dissection. Once the desired foramen is located, another small incision is made over the desired foramen that is large enough to allow insertion of the stimulation lead. The stimulation lead is inserted through the incision. Surgically implanting the stimulation lead in this manner near the patient's sacral nerve can cause patient complications, create significant patient's recovery time, and create a significant expense to the healthcare system. An example of the previous surgical method to implant a neurostimulation lead is described in Medtronic, “InterStim® Therapy Sacral Nerve Stimulation For Urinary Control Therapy Reference Guide,” Section 5 InterStim Device Implantation Procedure, pp. 51-52 (1999).
For the foregoing reasons, there is a need for a less invasive surgical instrument set for performing a method of implanting a neurostimulation lead in a patient through a foramen of the sacrum in relation to a sacral nerve, whereby patient surgical complications, surgical recovery time, and surgical costs are reduced while maintaining the substantial patient benefits of neurostimulation of the sacral nerve.